Assistive Technologies

The Additive Manufacturing (AM) process uses a 3D printer to convert a filament into a three-dimensional manufactured object by melting the filament and depositing it in built-up layers to form the desired object, where the movement of the printing head is controlled by computer code. The automation of AM is limited and usually still requires human labor workflows, including the fundamental step of removing the finished object from the printer platform. NASA Ames Research Center has developed a novel method to increase automation of AM by embedding additional instructions into the manufacturing toolpath to create manufacturing tools in situ, such as linear springs on the printer platform, and to instruct movement of the printers parts to autonomously move the finished object off the platform. The technology eliminates the need for humans in the loop for high-throughput applications. Testing can also be integrated into the manufacturing toolpath.

Researchers at NASA Marshall Space Flight Center have developed a novel method for interim, in situ dimensional inspection of additively manufactured parts. Additive manufacturing processes currently have limited monitoring capabilities, offering users little to no options in mitigating the high levels of product and process failures. This technology uses both infrared (IR) and visual cameras that allow users to monitor the build in real-time and correct the process as needed to reduce the time and material wasted in parts that will not meet quality specifications. The technology is especially useful for the in-process inspection of a parts internal features (e.g., fluid channels and passages), which cannot be easily inspected once the print is complete. The technology has the potential to enable the implementation of a closed-loop feedback system, allowing systems for automatic real-time corrections.

Researchers at NASA Langley Research Center have developed a much more reliable non-destructive evaluation method based on infrared thermography. The method provides transient temperature profiles of the surface, including the melt pool, at each step/layer. This system can measure material properties and detect defects during the additive manufacturing process. It will allow for characterization of the deposition quality and also detection of deposition defects such as voids, crack, and disbonds as the structure is manufactured layer by layer. The information, in the form of quantitative inspection images, can be archived with the manufactured part to document structural integrity. This is a more effective way of determining flaws or deposition quality during the build process.

Additive manufacturing enables unrivaled design freedom and flexible fabrication of components from a wide range of materials including metals, composites, polymers, and ceramics. The near net shape parts are made by processes like sequential melting or layer-by-layer material deposition with a complex set of processing variables. The sequential nature of the process means that every step can impact the next and thus, tools to evaluate that risk before and during manufacturing are necessary. Inventors at the NASA Langley Research Center have developed a novel method to model and ingest point-wise process data to evaluate an additive manufacturing build and its file for issues by highlighting potential anomalies or other areas where the build may have issues with fusion of the material. The technique was originally developed for use in tandem with powder bed fusion additive manufacturing for aerospace parts and is capable of being used on consumer grade computers.

Innovators at the NASA Langley Research Center have developed a manufacturing technique to generate recyclable feedstocks for on-demand additive manufacturing. Additive manufacturing is a rapidly advancing art with significant recent improvements in starting materials. One common limitation has been that produced articles cannot be recycled without substantial energy costs. Development of a manufacturing technique that can generate precise, mechanically robust articles that could be reverted to feedstock for use in subsequent article manufacturing would be highly desirable for applications including long duration extra-terrestrial exploration mission planning. NASA's new manufacturing technique uses polymer-coated epoxy micro-particle systems as a recyclable feedstock material that can be used not only for in-space additive manufacturing during long-term human spaceflight but also for a wealth of applications on Earth. The resulting articles are more chemically and mechanically robust compared to the state-of-the-art materials used for most 3D printing applications.

Powder-based AM methods typically require post-fabrication component cleaning to remove residue powder from the surface and crevices of the part, a task that becomes increasingly difficult and time consuming with part complexity. Methods currently available to clean AM parts have significant drawbacks. Immersive cleaning using solvents or solutions can cause powder clumping. Forms of blasting (e.g., wet, bead, hydro, bristle, vacuum, etc.) work on line-of-site surfaces but are ineffective for recessed cavities. Such cleaning is typically manual, highly time consuming, and requires careful use of personal protective equipment to avoid powder inhalation. Thus, the AM market would benefit from a more automated, rapid, and effective method for cleaning complex parts.

NASA Marshall Space Flight Center, in collaboration with the University of Alabama, has developed a contact-free support structure used to fabricate overhang-type geometries via EBAM. The support structure is used for 3-D metal-printed components for the aerospace, automotive, biomedical and other industries. Current techniques use support structures to address deformation challenges inherent in 3-D metal printing. However, these structures (overhangs) are bonded to the component and need to be removed in post-processing using a mechanical tool. This new technology improves the overhang support structure design for components by eliminating associated geometric defects and post-processing requirements.

The history of construction materials and methods has evolved over time, with Portland cement concrete being the most widely used material on Earth. Constructing habitats and infrastructure on the Moon and Mars, however, requires a different approach given the lack of such conventional construction resources and materials. Recognizing the need for in-situ resource utilization (ISRU) to support long-duration human missions to the Moon and Mars, NASA's Kennedy Space Center and Sidus Space have developed a novel three-dimensional print head apparatus using regolith-polymer mixtures as a building material. The invention paves the way for enabling the construction of habitats and other critical infrastructure on the Moon and other planetary bodies using available resources. The Regolith-Polymer 3D Printing System can also be adapted to work with other crushed rock materials or mixtures depending on resource availability at construction sites.

NASA has developed a novel approach for macroscale biomaterial production by combining synthetic biology with 3D printing. Cells are biologically engineered to deposit desired materials, such as proteins or metals, derived from locally available resources. The bioengineered cells build different materials in a specified 3D pattern to produce novel microstructures with precise molecular composition, thickness, print pattern, and shape. Scaffolds and reagents can be used for further control over material product. This innovation provides modern design and fabrication techniques for custom-designed organic or organic-inorganic composite biomaterials produced from limited resources.

NASA Langley Research Center has developed 3-D imaging technologies (Flash LIDAR) for real-time terrain mapping and synthetic vision-based navigation. To take advantage of the information inherent in a sequence of 3-D images acquired at video rates, NASA Langley has also developed an embedded image processing algorithm that can simultaneously correct, enhance, and derive relative motion, by processing this image sequence into a high resolution 3-D synthetic image. Traditional scanning LIDAR techniques generate an image frame by raster scanning an image one laser pulse per pixel at a time, whereas Flash LIDAR acquires an image much like an ordinary camera, generating an image using a single laser pulse. The benefits of the Flash LIDAR technique and the corresponding image to image processing enable autonomous vision based guidance and control for robotic systems. The current algorithm offers up to eight times image resolution enhancement and well as a 6 degree of freedom state vector of motion in the image frame.